1. Field
The present disclosure relates generally to spacecraft attitude and orbital control systems, and specifically a spacecraft attitude control system for use in earth orbiting satellites and spacecraft orbit and attitude control of spacecraft of a novel very long baseline gravitational wave detection satellite configuration located near the sun-earth Lagrangian points L3, L4 and L5, utilizing the control of solar radiation pressure by the use of electrically controllable variable reflection glass panels to provide the required torques and forces.
2. Description of the Related Art
Earth orbiting satellites are known and have been utilized for a large number of purposes, such as communications, navigation, weather observation, and research. The orbital elements of these satellites vary greatly, depending on the purpose of the satellite. Satellites in general are not restricted to earth orbits as they may orbit the sun or other planets. Regardless of mission, most satellites undergo several distinct phases requiring substantial forces and torques: launch, injection into an intermediate orbit, and injection into the operational orbit. The control forces and torques needed for these phases are significant. However, once the satellite is placed into its operational orbit, the torques required for attitude control are more easily manageable, and, in the case of the novel gravitational wave detection satellite configuration, the forces for orbital control are also more easily manageable.
Typically, the attitude of satellites is controlled by actuators that comprise chemical or electrical thrusters. Such satellites may include electrically powered reaction wheels (also known as momentum wheels) to aid in attitude control. The problem with using such thrusters can be the transient attitude disturbances they create and the resulting disturbance of the pointing of narrow communication beams or even narrower beams of optical payloads. Additionally, the thruster fuel usage may adversely affect the launch mass of the satellite if the satellite is intended for long duration operation. Adding to these problems, momentum wheels used for attitude control require periodic thruster actuation to keep their angular momentum within prescribed limits.
The orbital control of satellites has also used chemical and electrical thrusters, but require greater use of fuel and/or power over the satellite lifetime, and thus are often the limiting factor in satellite life.
What is needed is a system and method for controlling the attitude of satellites that minimizes transient attitude disturbances and permits more precise control. In orbits where satellite orbital control needs are minimal, what is needed is a system and method that controls forces in such a way that essentially allows for unlimited satellite lifetime, and also does not contaminate any sensitive instruments onboard the satellite.